DDSFileHandler.h

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#ifndef DDSFILEHANDLER_H
#define DDSFILEHANDLER_H

//                                                                          //
// DDSFileHandler                                                           //
//                                                                          //
// Package: DDS (Data Dispatcher System).                                   //
//                                                                          //
// S. Kasahara 5/2001                                                       //
// Purpose: Interact with system to determine next available file for a     //
//          given DDS::EDataSource.  Will construct and return the full     //
//          file path name of the next file when requested.                 //
#include <iosfwd> // ostream forward decl.
#include <vector>

#include "Dispatcher/DDS.h"

class DDSFileHandler;

std::ostream& operator << (std::ostream& ms, DDSFileHandler* dfh);

class DDSFileHandler {

public:
  // Typedefs and enumerations.
  typedef std::vector<std::string> FileIndex;
  typedef FileIndex::iterator FileIndexItr;
  typedef FileIndex::const_iterator FileIndexConstItr;

  // Constructor and destructor.
  DDSFileHandler (DDS::EDataSource datasource,bool offLine = false);   
  virtual ~DDSFileHandler (); // destructor       

  // State testing member functions.
  std::string GetCurrentFileName() const;
  DDS::EDataSource GetDataSource() const { return fDataSource; }
  std::string GetSymLinkTargetName();
  bool IsOffLine() const { return fOffLine; }
  bool IsValid() const { return fValid; }
  bool NewFileAvailable();
  std::ostream& Print(std::ostream& ms) const;
  
  // State changing member functions
  std::string GoToFile(std::string filename="");
  std::string GoToNextFile();
  std::string GoToSymLinkFile();

private:

  // State testing member functions
  bool IsModifiedDirectory() const;
  bool IsModifiedSymLink() const;

  // State changing member functions
  Int_t BuildFileIndex();         
  std::string BuildFullFilePathName(std::string filename);         

  // Data members.
  DDS::EDataSource fDataSource; // source of data
  std::string fDataSourceEnv;   // env variable pointing to source directory
  std::string fDataSourceDir;         // directory of source data files
  std::string fLocalDataSourceDir;    // local directory of source data files
  std::string fSymLink;           // pathname of symbolic link to target file 
  std::string fSymLinkTarget;     // pathname of current target of sym link
  Long_t fSymLinkModTime;        // symbolic link modification time
  Long_t fSourceDirModTime;      // source directory modification time
  std::string fLastServedFile;   // last served file
  bool   fValid;                 // flag indicating validity of FileHandler
  FileIndex fFileIndex;          // index of files in source directory
  FileIndexItr fFileIndexItr;    // iterator points to current file in index 
  bool   fOffLine;               // file handler will use symlink offlinefile
 
  ClassDef(DDSFileHandler,0)  // MINOS Data Dispatcher File Handler
};

#endif              // DDSFILEHANDLER_H

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